Due to the recent drastic growth of data communication, there exists an ever-increasing demand for using unlicensed spectrum such as TV White Space (TVWS) in order to overcome the shortage of frequency bands. In this context, many attempts have been taken to deploy a high-speed wireless data communication system such as Wireless Local Area Network (WLAN) in the TVWS frequency band.
However, it is not easy to introduce unlicensed spectrum to a cellular wireless data transmission system such as Long Term Evolution (LTE) in which a Base Station (BS) should perform a transmission and reception procedure at a predetermined time point, because exclusive occupation of a frequency channel is impossible in view of the nature of the unlicensed spectrum that tolerates interference.
Considering that various devices can use an unlicensed frequency band without being licensed to supplement lacking frequency resources, an LTE system may coexist with a WLAN system in the unlicensed frequency band. To allow the LTE system to exclusively occupy a frequency, for a normal operation, it is necessary to give considerations to co-existence between heterogeneous devices.
Especially, a technique for enabling co-existence in TVWS between a device conforming to Institute of Electrical and Electronics Engineers (IEEE) 802 which is currently widely deployed for wireless communication and a NON-802 device is under study.
WLAN in TVWS is under standardization in IEEE 802.11, and a co-existence scenario is being developed in IEEE 802.19.